The story emerging of Elliot Rodger’s violent musings prior to going on a deadly rampage Friday is disturbing to say the least.

From social media postings to YouTube videos, Rodger’s violent rants hinted at the coming massacre.

His parents, who are in “deep, deep grief” over the shooting, even tried to step in before Friday’s shooting spree.

In April, Rodger’s mother called one of her son’s counselors after seeing bizarre videos he had posted on YouTube. The counselor then called a mental health service who called police.

But Santa Barbara County Sheriff’s deputies who paid a visit to Rodger’s were left believing he was not a risk to others despite the alarming videos.

“Obviously, looking back on this, it’s a very tragic situation and we certainly wish that we could turn the clock back and maybe change some things,” Brown told CBS’ Face the Nation on Sunday.

“At the time deputies interacted with him, he was able to convince them that he was OK,” he said.

[The videos in this article are disturbing — Discretion is advised].

Rodger’s family said their son was in therapy and were concerned about their son’s behavior for months, if not years.

Doris A. Fuller, executive director of the Virginia-based Treatment Advocacy Center, said too little was done too late.

“Once again, we are grieving over deaths and devastation caused by a young man who was sending up red flags for danger that failed to produce intervention in time to avert tragedy,” Fuller said in a statement.

“In this case, the red flags were so big the killer’s parents had called police … and yet the system failed,” she said.

But most frightening is the 141-page manifesto promising a “Day of Retribution” he emailed to his mother and counselor minutes before stabbing and killing three young men in his apartment, killing three more people and injuring 13 others by shooting them.

“We said right from the get-go that that kid was going to lose it someday and just freak out,” a high school classmate told The New York Times. “Everyone made fun of him and stuff.”

Most troubling is Rodger’s words and demeanor in YouTube videos posted before the killings.

“On the week leading up to date I set for the Day of Retribution, I uploaded several videos onto YouTube in order to express my views and feelings to the world, though I don’t plan on uploading my ultimate video until minutes before the attack, because on that video I will talk about exactly why I’m doing this,” Rodger wrote.

In the final video posted Friday, he sits in a black BMW telling the world about the pleasure he would derive in killing.

“I’ll take great pleasure in slaughtering all of you,” he said.

Image via YouTube